Miller Electric S-21E User manual

MiIIe~
November1996 Form: TM-1571
Effective With Serial No. JJ507797
TECHNICAL MANUAL
Service And Parts
Wire Feed Equipment
A WARNING
SERVICING can be hazardous.
• Have all service procedures performed only by
qualified persons following standard safety
practices.
Use MILLER Testing Booklet (Part No.
150 853) when servicing this unit.
Use only genuine MILLER replacement
parts.
S-21E
U For help, call Factory ~U~r FAX: U Or write to:
Service Department: 14-735-4136 MILLER Electric Mfg. Co.
414-735-4505 L................J RO. Box 1079
Appleton, WI 54912 USA
coverjml — SB-124 467
© 1996 MILLER Electric Mfg. Co.
PRINTED IN USA

OM-1571B — 3/91
TABLE OF CONTENTS
Section No. Page No.
SECTION 1 - SAFETY PRECAUTIONS AND SIGNAL WORDS
1-1. General Information And Safety 1
1-2. Safety Alert Symbol And Signal Words 1
1-3. Safety Precautions 1
SECTION 2- SHIPPING AND STORAGE
2-1. Preparation For Reshipment 2
2-2. Storage 2
SECTION 3— SPECIFICATIONS
3-1. Description 3
SECTION 4- INSTALLATION OR RELOCATION
4-1. Location 3
4-2. Drive Roll Installation 3
4-3. Welding Gun Connections 5
4-4. Shielding Gas Installation 5
4-5. 14-Pin Plug Connection 6
4-6. Welding Wire Installation 6
4-7. Welding Wire Threading 7
4-8. Adjust The Hub Tension 8
4-9. Welding Cable Connection 8
4-10. Feeding Welding Wire 8
SECTION 5-OPERATOR CONTROLS
5-1. Power Switch 9
5-2. Wire Speed Control 9
SECTION 6— SEQUENCE OF OPERATION
6-1. Gas Metal Arc (GMAW) And Flux Cored Arc (FCAW) Welding 9
6-2. Shutting Down 10
SECTION 7- THEORY OF OPERATION
7-1. Theory Of Operation 10
Diagram 7-1. Block Diagram For Wire Feeder 11
Diagram 7-2. Block Diagram For SpotlBurnback Time Control Option 12

Section No. Page No.
SECTION 8- TROUBLESHOOTING
8-1. Testing Instruments And Information
8-2. Circuit Board Handling Precautions
8-3. Troubleshooting
Diagram 8-1. Troubleshooting Circuit Diagram For Wire Feeder
8-4. Motor Board PCi Testing Information
Diagram 8-2. Troubleshooting Circuit Diagram For Motor Control
Board PCi
8-5. Optional SpotlBurnback Board PC2 Testing Information
Diagram 8-3. Troubleshooting Circuit Diagram For Optional Spot/Burnback
Board PC2
SECTION 9- COMPONENT IDENTIFICATION AND LOCATION
Figure 9-1. Component Identification And Location
SECTION 10— MAINTENANCE
10-1. Routine Maintenance
10-2. Aligning Drive Roll And Wire Guide
10-3. Reinstallation Of Hub Assembly
10-4. Brush Inspection And Replacement
10-5. Overload Protection
SECTION 11 - ELECTRICAL DIAGRAMS
Diagram 11-1.
Diagram 11-2.
Diagram 11-3.
Diagram 11-4.
Diagram 11-5.
Circuit Diagram For S-21 E Effective With Serial No.
JJ507797 And Following
Wiring Diagram For S-21 E Effective With Serial No.
JJ507797 And Following
Circuit Diagram For Motor Control Board PCi Effective
With Serial No. JJ507797 And Following
Circuit Diagram For Optional SpotlBurnback Board PC2
Effective With Serial No. JJ507797 Thru JK742028
Circuit Diagram For Optional Spot/Burnback Board PC2
Effective With Serial No. JK742029 And Following
29
29
30
31
32
SECTION 12— PARTS LIST
LIST OF CHARTS AND TABLES
Table 3-1. Specifications
Table 8-1. Troubleshooting
Table 10-1. Maintenance Schedule
Table 11-1. List Of Circuit Diagrams And Wiring Diagrams
3
15
25
28
14
14
14
16
17
18
20
22
24
25
26
26
27
27

SECTION 1 - SAFETY PRECAUTIONS AND SIGNAL WORDS
1-1. GENERAL INFORMATION AND SAFETY
This manual provides theory of operation along with
specific operating, testing, and troubleshooting proce-
dures. It also includes precautionary information rele-
vant to these procedures. This manual can be an effec -
tive tool in the hands of a trained serviceperson. How-
ever, it does not and cannot take the place of previous
training nor safety-conscious service work. If any doubt
arises about the specific application of procedures pre -
sented, or if problems arise which are not covered in this
manual, contact the factory Service Department before
proceeding further.
1-2. SAFETY ALERT SYMBOL AND SIGNAL
WORDS
The following safety alert symbol and signal words are
used throughout this manual to call attention to and
identify different levels of hazard and special instruc -
tions.
This safety alert symbol is used with the signal
A
words WARNING and CAUTION to call atten -
tio n to the safety statements.
A
WARNING statements identify procedures or
practices which must be followed to avoid seri -
ous personal injury or loss of life.
CAUTION statements identify procedures or
A
practices which must be followed to avoid minor
personal injury or damage to this equipment.
IMPORTANT statements identify special instructions
necessary for the most efficient operation of this equip -
ment.
1-3. SAFETY PRECAUTIONS
A
W ARNING: ELECTRIC SHOCK can kill.
S Do not touch live electrical parts.
• Protect yourself with dry insulating gloves
and clothing.
• Insulate yourself from ground by using
rubber9loves and insulating floormats when
power is applied to the unit.
• Shut down unit and disconnect input power
when servicing unless the procedure specifi -
cally requires an energized unit.
• Do not leave live unit unattended.
ARC RAYS, SPARKS, AND HOT SURFACES
can burn eyes and skin; NOISE can damage
hearing.
• Wear correct eye, ear, and body protection.
FUMES AND GASES can seriously harm
your health.
• Keep your head out of the fumes.
• Ventilate to keep from breathing fumes and
gases.
• If ventilation is inadequate, use approved
breathing device.
• Read Material Safety Data Sheets (MSDSs)
and manufacturer’s instructions for any
materials used.
WELDING WIRE can cause puncture
wounds.
• Do not point gun towa rd any part of the body,
any conductive surface, or other personnel.
HOT METAL, SPATrER, AND SLAG can
cause fire and burns.
• Watch for fire.
• Have a fire extinguisher nearby and know
how to use it.
• Do not use near flammable material.
• Allow work and equipment to cool before
handling.
MOVING PARTS can cause serious injury.
• Keep away from moving parts.
HOT SURFACES can cause severe burns.
• Allow cooling period before servicing.
MAGNETIC FIELDS FROM HIGH CURRENTS
can affect pacemaker operation.
• Wearers should consult their doctor before
going near the servicing of arc welding equip -
ment or any arc welding operations.
5-21E TM-1571 Page 1

SECTION 2- SHIPPING AND STORAGE
A
PREPARATION FOR RESHIPMENT
WARNING: ELECTRIC SHOCK can kill.
• Do not touch live electrical parts.
• Shut down wire feeder and welding power
source, and disconnect input power employ -
ing lockout/tagging procedures before
preparing unit for shipping.
Lockout/tagging procedures forwire feedercon -
sist of disconnecting interconnecting cord, and
for welding power source consist of padlocking
line disconnect switch in open position, remov-
ing fuses from fuse box, or shutting off and red-
tagging circuit breaker or other disconnecting
device. Stop engine, and disconnect negative
(—) battery cable from battery on welding gen -
erators.
1. Disconnect interconnecting cord from rear of wire
feeder.
2. Disconnect weld cable from drive assembly.
3. Disconnect and remove any remote controls or
devices.
4. Disconnect shielding gas (and water if applica -
ble) hoses from wire feeder.
5. Disconnect gun from wire feeder.
6. Secure welding wire to spool/reel, and remove
wire spool or reel from wire feeder.
7. Tape plastic around top and sides of unit.
8. Securely tie and/or tape cardboard over top and
around sides of unit. Use original shipping carton
if available.
IMPORTANT: Do not ship without a cardboard carton.
Not only do costs increase dramatically but the unit is
more subject to loss or damage without a carton.
9. If sending unit to factory, ship unit as directed by
factory Service Department or Transportation
Department.
A
STORAGE
WARNING: ELECTRIC SHOCK can kill.
• Do not touch live electrical parts.
• Shut down wire feeder and welding power
source, and disconnect in put power employ -
ing lockout/tagging procedures before storing
unit.
Lockout/tagging procedures forwirefeedercon -
sist of disconnecting interconnecting cord, and
for welding power source consist of padlocking
line disconnect switch in open position, remov-
ing fuses from fuse box, or shutting off and red-
tagging circuit breaker or other disconnecting
device. Stop engine, and disconnect negative
(—) battery cable from battery on welding gen -
erators.
1. Disconnect interconnecting cord from rear of wire
feeder.
2. Disconnect weld cable from drive assembly.
3. Disconnect and remove any remote controls or
devices.
4. Disconnect shielding gas (and water if applica-
ble) hoses from wire feeder.
5. Disconnect gun from wire feeder.
6. Secure welding wire to spool/reel, and remove
wire spool or reel from wire feeder.
7. Clean outside of unit.
8. Remove wrapper.
9. Using dry compressed air, clean inside of unit.
10. Reinstall wrapper.
11. Select a storage location that least subjects the
unit to wide temperature variation, dust, dirt, and
corrosive vapors.
12. Carry unit to storage location.
13. Cover unit with plastic or suitable tarp.
TM-1571 Page 2 5-21E

SECTION 3- SPECIFICATIONS
Table 3-1. Specifications
Input Power
Requirements Electrode
Wire
Diameter Capacity Wire
Spool
Capacity
Electrode Wire
Feed Speed
Weight
Net Ship
10 to 20 lb.
24 VAC
3.5 Amps
50/60 Hz
.O23thru .045 in.
(0.6 thru 1.1 mm)
(4.5 to 9 kg)
8 in. (203mm) spools
up to 60 lb.
(27.2 kg)_coils
75-600 ipm
(1.9-15.2 mom)
at 24 VA~
30 lbs.
(13.6 kg)
33 lbs.
(15 kg)
SB-124 467
Figure 3-1. Overall Dimensions
3-1. DESCRIPTION
This unit is a semiautomatic constant speed wire feeder
which operates on 24 volts ac. The feeder is designed
for connection to a constant voltage (CV) type power
source through a 14-pin connector. If 115 volts ac is the
only power available for use with the feeder, the optional
power supply adapter Model PSA-2 115/24 should be
used to convert the power to 24 volts ac.
The case can be tightly latched to help keep out dust and
dirt.
SECTION 4- INSTALLATION OR RELOCATION
4-1. LOCATION (Figure 3-1)
The service life and efficiency of this unit and associated
components are reduced when they are subjected to
high levels of dust, dirt, moisture, corrosive vapors, and
extreme heat.
A proper installation site should be selected for the wire
feeder if the unit is to provide dependable service. Lead
lengths must be considered when installing the unit. A
slot is provided in the base of the unit to fit over the lifting
eye on welding power sources so equipped. Suitable
space should be maintained around the unit for making
necessary connections and for maintenance functions.
4-2. DRIVE ROLL INSTALLATION (Figure 4-1)
A
WARNING: ELECTRIC SHOCK can kill.
• Do not touch live electrical parts.
• Shut down wire feeder and welding power
source, and disconnect input power employ -
ing lockout/tagging procedures before in -
specting or installing.
Lockout/tagging procedures for wire feeder con -
sist of disconnecting interconnecting cord, and
for welding power source consist of padlocking
line disconnect switch in open position, remov-
ing fuses from fuse box, or shutting off and red-
tagging circuit breaker or other disconnecting
device. Stop engine, and disconnect negative
(—) battery cable from battery on welding gen -
erators. TM-1571 Page 3
10-112 In.
(267 mm)
22-1(2 in.
(572 mm)
S-21E

• OPTIONAL
Pressure Roll
Assembly
(Shown In Open
PosItion)
It is necessary to install the required drive rolls when set -
ting up this unit and also when changing wire sizes.
IMPORTANT: Base drive roll selection on the following
recommendations:
The dual-grooved drive roll provided with the feeder ac -
commodates .023 through .045 in. (0.6 through 1.1 mm)
wire. This drive roll has both a “‘I” groove and a “‘I”
knurled groove. Use the “V” groove for feeding .023 and
.030 in. (0.6 and 0.76 mm) wire. Use the “V” knurled
groove for feeding .035 and .045 in. (0.89 and 1.1 mm)
wire. The wire size for each groove is stamped on the
side of the drive roll. When the drive roll is installed in the
feeder, the wire size stamp for the unused groove will be
visible.
The 50 Series wire feeder style drive rolls may be used
with this feeder, but, due to the flat idler pressure roll
used, a knurled drive roll is recommended when feeding
.035 and .045 (.089 and 1.1 mm) wire.
A
W ARNING: ELECTRIC SHOCK can kill.
Do not store metallic objects in this compart -
ment. The motor drive assembly is electri -
cally hot whenever the welding circuit is ener -
gized.
Loose metal objects in this compartment may
create an electrical path between the weld out -
put circuit and any metal surfaces or compo-
nents resulting in electric shock.
IMPORTANT: Both types of 50 Series style drive rolls
can be reversed for reuse when they become worn. Re -
verse rolls to position unused groove(s) to feed wire.
The dual-grooved drive roll pro vided with this feedercan
be reversed, but only to feed a different size wire.
1. Unlatch and open left case access door.
2. Loosen pressure adjustment knob, and pivot
knob free of pressure arm.
3. Pivot pressure arm away to expose drive roll
carrier.
4. For dual-grooved roll supplied with feeder:
a. Choose the proper groove.
b. Slide drive roll onto drive roll mounting hub with
chosen groove toward inside of machine. The
wire size for the unused groove will be visible
after installation.
c. Align the drive roll with holes.
d. Insert securing screws, and tighten.
Hub
Wire
• Spring
9
Retaining
Ring
Ret. 50497
Figure 4-1. Wire Feeder Components
GunlFeeder
connector
Securing Knob
Ref. SB-125 923
TM-1571 Page 4
5-21E

5. For 50 Series style one-piece drive rolls: B. Gun Trigger (Figure 5-1)
a. Slide drive roll onto drive roll mounting hub.
b. Align drive roll with holes.
c. Insert securing screws, and tighten.
6. For 50 Series style split drive rolls:
a. Align holes on pair of split drive rolls.
b. Insert securing screw.
c. Slide drive rolls onto drive roll mounting hub.
d. Align drive rolls with holes.
e. Insert securing screws, and tighten.
IMPORTANT: Horizontal alignment of the drive roll on
the drive roll mounting hub with the wire guide is factory
set and should not require readjustment. If readjustment
becomes necessary, see Section 10-2.
7. Close and secure left case access door.
4-3. WELDING GUN CONNECTIONS (Figures 4-1
And 5-1)
A
WARNING: ELECTRIC SHOCK can kill.
• Do not touch live electrical parts.
• Shut down wire feeder and welding power
source, and disconnect input power employ -
ing lockout/tagging procedures before work -
ing on feeder.
Lockout/tagging procedures for wire feeder con -
sist of disconnecting interconnecting cord, and
for welding power source consist of padlocking
line disconnect switch in open position, remov-
ing fuses from fuse box, or shutting off and red-
tagging circuit breaker or other disconnecting
device. Stop engine, and disconnect negative
(—) battery cable from battery on welding gen -
erators.
IMPORTANT: A hole ispro vided in the nameplate form-
stallation of a gun requiring an opening for an external
gas line. Remove snap-in blank before installation.
A. Gun Connector To Drive Assembly (Figure 4-1)
1. Unlatch and open left case access door.
2. Loosen gun/feeder connector securing knob on
the wire drive housing.
3. Insert gun/feeder connector through the access
hole in the front panel.
4. Insert gun/feeder connector into drive housing
with the outlet wire guide as close to the drive rolls
as possible without touching, and tighten the se -
curing knob.
5.
S-21E
Close and secure left case access door.
‘9=
TRIGGER
RECEPTACLE
Connect gun trigger plug to trigger receptacle on the
front panel as follows: align keyways, insert gun plug
into trigger receptacle, and rotate threaded collar fully
clockwise.
4-4. SHIELDING GAS INSTALLATION (Figures
4-2 And 4-3)
A
WARNING: PRESSURIZED CYLINDERS can
rupture causing serious personal injury and
loss of life; FALLING CYLINDERS can cause
serious injury and equipment damage.
• Keep cylinders away from welding or other
electrical circuits.
• Never allow a welding electrode to touch any
cylinder.
• Always fasten cylinder securely to running
gear bracket, a wall, or other stationary sup-
port.
A. Gas Cylinder (Customer Supplied)
Chain the cylinder to a wall or other stationary support to
prevent the cylinder from falling over and breaking off
the valve. If optional power source running gear is used,
secure gas cylinder to running gear with supplied chain.
B. Regulator/Flowmeter (Customer Supplied)
1. With the cylinder securely installed, remove the
cylinder cap, stand to one side of cylinder valve,
and open valve slightly. When gas flows from cyl -
inder, close valve. This procedure blows out dust
or dirt that may have accumulated around the
valve seat.
IMPORTANT: A gasket should be installed to prevent
leaks. Do not use lubricants or sealing agents.
2. The regulator/flowmeter must be properly
equipped with a stem, nut connectors, and gas -
ket for use with either CO2
cylinders or inert gas
type cylinders.
3. Install gas regulator/flowmeter onto gas cylinder
valve; keep the face of the regulator/flowmeter
gauge in vertical position, and tighten stem nut
securely to gas cylinder valve.
4. A shielding gas fitting is provided on the rear of
the wire feeder. Obtain a suitable hose with
5/8-18 right- hand fitting. Attach one end of the
gas hose to this fitting. Attach the other end of the
gas hose to the regulator/flowmeter.
TM-1571 Page 5

Figure 4-2. Typical RegulatorlFlowmeter Installation
4-5. 14-PIN PLUG CONNECTION (Figures 4-3 And
4-4)
The 14-pin plug PLG1 00, on the end of the interconnect -
ing cord, provides a junction point for connecting the
wire feeder to a welding power source. This connection
provides 24 volt ac power, and contactor control when
used with a constant voltage (CV) power source with a
14-pin receptacle. To make connections, align keyway,
insert plug, and rotate threaded collar fully clockwise.
The pins on plug PLG 100 are defined in relation to both
the power source and wire feeder. The welding power
source provides six functions to the wire feeder. The
pins are designated as follows:
Pin A: Up to 10 amperes of 24 volts ac, 60 Hz, with re -
spect to socket G (circuit common); protected by fuse in
welding power source.
Pin B: 24 volts ac input power to energize the weld con -
tactor. The feeder sends back 24 volts ac by means of a
contact closure from pin A to pin B.
Pin G: 24 volts ac circuit common; also connected to
welding power source chassis.
IMPORTANT: The remaining pins in the receptacle are
not used by the feeder.
Shielding Gas
valve Fitting,
14-Pin
Plug
Gas cylinder
Valve
Argon or Argon
Mix cylinder
SB-109 492
Ref. S-0004
Figure 4-4. Front View Of 14-Pin Plug With Pin
Locations
4-6. WELDING WIRE INSTALLATION (Figure 4-5)
A
WARNING: ELECTRIC SHOCK can kill.
• Do not touch live electrical parts.
• Shut down wire feeder and welding power
source, and disconnect input power em ploy -
ing lockout/tagging procedures before work -
ing on feeder.
Lockout/tagging procedures forwire feeder con -
sist of disconnecting interconnecting cord, and
for welding power source consist of padlocking
line disconnect switch in open position, remov-
ing fuses from fuse box, or shutting off and red-
tagging circuit breaker or other disconnecting
device. Stop engine, and disconnect negative
(—) battery cable from battery on welding gen -
erators.
A
CAUTION: LOOSE WELDING WIRE can
cause Injury.
• Keep a firm hold on the wire during installa -
tion, removal, and threading operations.
Spooled wire has a tendency to unravel rapidly
when loosened from the spool.
SA-125 924 IMPORTANT: If it should become necessary to replace
any part of the hub assembly see hub assembly rein -
stallation instruction in Section 10-3.
Flow
Adjustment
CO2
Washer CO2 cylinder
CO2 Installation Argon Installation
Wire Feed
Weld Cable
Connection
Opening
Figure 4-3. Rear Panel View
TM-1571 Page 6 5-21E